Therefore, this is the key difference between chlorophyll and carotenoids. Furthermore, there are several types of chlorophylls; chlorophyll a, b, c and d while there are only two types of carotenoids. They are the carotenes and xanthophylls.
Hence, it is another difference between chlorophyll and carotenoids. Moreover, both types of pigments can absorb light. But, unlike carotenoids, only chlorophylls can transfer light to the photosynthetic pathway directly. Furthermore, there is also a structural difference between chlorophyll and carotenoids. Chlorophylls contain a porphyrin rings in their structure while carotenoids contain two small six carbon rings and a long carbon chain.
Chlorophylls and carotenoids are two types of plant pigments. The key difference between chlorophyll and carotenoids is the reflecting colours.
Chlorophylls reflect green colour wavelength; hence, visible in green colour while the carotenoids reflect yellow to red colour wavelengths; hence, visible in yellow, orange and red in colours. Furthermore, chlorophylls are the primary photosynthetic pigments that involve directly with photosynthesis while the carotenoids are accessory pigments that transfer absorbed light to chlorophylls due to the inability of transferring directly to the photosynthetic pathway.
There are several types of chlorophylls namely chlorophyll a, b, c, and d while there are two main types of carotenoids namely carotenes and xanthophylls.
Thus, this summarizes the difference between chlorophyll and carotenoids. Szalay, Jessie. When that reflected light enters your eyes, you perceive plants as green. Chlorophyll's role is to absorb light for photosynthesis. There are two main types of chlorophyll: A and B. Chlorophyll A's central role is as an electron donor in the electron transport chain. Chlorophyll B's role is to give organisms the ability to absorb higher frequency blue light for use in photosynthesis. Chlorophyll is a pigment or a chemical compound that absorbs and reflects specific wavelengths of light.
Chlorophyll is found within cells in the thylakoid membrane of an organelle called the chloroplast. Pigments such as chlorophyll are useful for plants and other autotrophs , which are organisms that create their energy by converting light energy from the sun into chemical energy.
The primary role of chlorophyll is to absorb light energy for use in a process called photosynthesis — the process by which plants, algae and some bacteria convert light energy from the sun into chemical energy. Light is made up of bundles of energy called photons.
Pigments like chlorophyll, through a complex process, pass photons from pigment to pigment until it reaches an area called the reaction center. After photons reach the reaction center, the energy is converted into chemical energy to be used by the cell.
The main pigment used by organisms for photosynthesis is chlorophyll. In the autumn, as the quantity of chlorophyll in the leaf declines, the carotenoids become visible and produce the yellows and reds of autumn foliage. Figure 3.
Note again the system of alternating single and double bonds that in this molecule runs along the hydrocarbon chain that connects the two benzene rings.
As in chlorophyll, the electrons of the double bonds actually migrate though the chain and also make this molecule an efficient absorber of light.
Many animals use ingested beta-carotene as a precursor for the synthesis of vitamin A. John W. The linker chlorophyll molecules probably play an important role in excitation energy transfer between Lhca antennas and from Lhca to the PSI core [ 20 , 25 , 26 ].
At closer look Figure 4f , the redox co-factors in the core reaction center are arranged into two arms that are located on either side of the region where two groups of helices interact with each other. Two chlorophylls form P and then each arm contains two monomeric chlorophyll molecules the second one being in the equivalent position to the pheophytin present in photosystem II followed by one quinone molecule.
When P is oxidized, both arms of the electron transport pathway are able to work as it was reported that the electron can pass either down the B-branch or the A-branch [ 27 ]. Chlorophyll and carotenoid can be isolated as free pigments, detached from the pigment-protein complexes, by organic solvent extraction.
Important aspects such as the choice of organic solvents, light exposure and working temperature should be considered while isolating pigments. Based on the structure, chlorophyll is characterized with polar macrocycle ring with non-polar hydrocarbon tail. The structural difference between Chl b and Chl a is by having an aldehyde group in place of the methyl group at the macrocycle side group. This change is effecting the polarity of Chl b to be more polar in comparison to Chl a.
In the case of carotenoid, structural difference can be seen from the number of conjugated double bonds and the presence of oxygen atoms. During extraction, exposure of light should be avoided to reduce photodamage of the pigments. Temperature is also important. It is recommended to conduct extraction at lower temperatures, for example, on ice or using liquid nitrogen, to minimize activity of enzyme e. Antioxidant agent can be also added during extraction to avoid any unwanted oxidation.
After successful isolation, liquid chromatography has been widely used as an effective technique to separate individual type of pigments and for further purification. In this technique, the pigment separation is based on the polarity which depends on the interaction of pigment with the stationary and mobile phases. Elution method either normal phase or reversed phase is chosen according to the type of pigment to be separated. In addition, the choice of liquid chromatographic methods, namely thin layer chromatography TLC , column chromatography CC and high-pressure liquid chromatography HPLC , is referred to the speed, resolution and quantity of sample [ 30 ].
Currently, ultra-fast liquid chromatography UFLC , a recent development of HPLC, has been used as a standard for liquid chromatography to achieve high-resolution data with low time consumption [ 31 ].
Purification with non-chromatographic method has also been developed, that is, purification method using dioxane has been effective to separate chlorophyll from most of the carotenoids and some lipids [ 32 ].
Various types of column absorbents used for chromatographic separation of plant pigments have been well reviewed [ 30 ]. Here, we used a silica C30 column attached to UFLC analytic to achieve well separation of carotenoids from Pleomele angustifolia leaf using elution gradient program with mixture of water, methanol and methyl tert-butyl ether to separate, at least, 7 dominant pigments within 25 min.
Figure 5. The detailed identification of pigments, based on the chromatographic, spectrophotometric and mass properties, is summarized in Table 1. UFLC chromatogram of pigment extract from chloroplast of Pleomele angustifolia detected at nm. Chromatographic, spectrophotometric and mass properties of pigments separated from the chloroplast of Pleomele angustifolia. Chl a could be eluted using 1. To achieve a pure, free carotenoid, saponification step is sometimes necessary to eliminate contamination of lipids and chlorophylls.
Moreover, carotenoid ester can be hydrolyzed to produce parent carotenoid by using this method [ 34 ]. CC is usually used for carotenoid isolation in high quantity of pigment extract. Generally, the purpose of CC is to separate mixtures into carotenoid fractions which are either having high purity to be processed to crystallization or low purity to be extensively separated with further chromatography, that is, HPLC [ 35 ]. Silica and alumina are frequently used as the absorbent in the CC with the normal phase elution to separate the distinct carotenoids; however, it is not easy to use this method to separate carotenoid isomers, that is, geometrical isomers, diastereoisomers, and so on.
Turcsi et al. High purity of isolated pigment can be achieved by HPLC and crystallization processes. UFLC analysis of the purified zeaxanthin shows that this carotenoid had a high purity of around Purification of zeaxanthin: a chromatogram detected at nm.
Chromatographic, spectrophotometric and mass properties of pigment are minimum requirements for pigment identification [ 35 ]. These properties for all purified pigments are shown in the Table 1.
The LCMS technique has provided a power tool for pigment identification [ 39 , 40 ]. This mass spectrum of Chl a agrees with the result that was reported [ 42 ]. Purification of Chl: a chromatogram detected at nm.
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